/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 *
 */
package io.github.interestinglab.waterdrop.filter

import io.github.interestinglab.waterdrop.config.{Config, ConfigFactory}
import io.github.interestinglab.waterdrop.apis.BaseFilter
import org.apache.spark.sql.catalyst.parser.ParseException
import org.apache.spark.sql.{Column, Dataset, Row, SparkSession}
import org.apache.spark.sql.functions.not

import scala.util.control.NonFatal

class Drop extends BaseFilter {

  var conf: Config = ConfigFactory.empty()

  /**
   * Set Config.
   * */
  override def setConfig(config: Config): Unit = {
    this.conf = config
  }

  /**
   * Get Config.
   * */
  override def getConfig(): Config = {
    this.conf
  }

  override def checkConfig(): (Boolean, String) = {
    val sparkSession = SparkSession.builder().getOrCreate()
    conf.hasPath("condition") match {
      case true => {
        try {
          sparkSession.sessionState.sqlParser.parseExpression(conf.getString("condition"))
          (true, "")
        } catch {
          case parseEx: ParseException =>
            (false, "failed to parse [condition], caught exception: " + parseEx.getMessage())
          case NonFatal(e) => (false, e.getMessage)
        }
      }
      case false => (false, "please specify [condition]")
    }
  }

  override def process(spark: SparkSession, df: Dataset[Row]): Dataset[Row] = {
    val conditionExpr = conf.getString("condition")
    df.filter(not(new Column(spark.sessionState.sqlParser.parseExpression(conditionExpr))))
  }
}
